reflections of a developing professional
  • Fear and Loathing in Adolescence

    Fear and Loathing in Adolescence

  • Keep Learning

    Keep Learning

Hand-y way to remember Unit Circle exact values

Confused, much?

Confused, much?

I was recently working with a Year 10 Mathematical Methods student, in preparation for the upcoming exams. She couldn’t remember the exact values of the Unit Circle angles, so I showed her a handy method of remembering. She was impressed (aw, shucks!), so I thought I’d share it here!

Step 1:

Label the thumb of your left hand “SINE”, your index finger “30”, your middle finger “45”, your ring finger “60” and your pinky “COS”. Draw a vinculum with the number 2 as the denominator on your palm. Or, draw divided by 2 on your palm – whichever works! :)

See below:

Marked Hand

 

Step 2:

Step 2 requires some imagination. I want you to imagine that there is a magic square root symbol floating in the air above your fingertips. Can you see it?

Magic Root

 

Step 3:

If you would like to know what the exact value of, say, Sine 30 degrees, fold down the finger with “30” on it. Like this:

20141115_172119

The Magic Root symbol goes over the digit left standing on the Sine side of the hand – in this case the thumb. The root of one (or just one), divided by two – the exact value of Sine 30 is one-half!

Can you also see how the Cosine of 30 can be found?

Below I have lowered the “45” digit – the Sine and Cosine of 45 both equal to root two divided by two! It’s magic!

20141115_172126

20141115_172136

 

This little memory trick has worked wonders for  me over the past few years, particularly with students who have found surds and fractions to be a frightening mix. I have taught this to students in Year 10, who have found it an invaluable tool in their understanding of the Unit Circle.

 

Here’s a challenge for you or your students. How can we include the exact values for the Tangent into this? :)

 

Twitter and Blogging..

Ok, it’s official, my head just exploded. Following an #edchat on Twitter will do that to you!

 

Head-Exploding

 

One of the great things about having a broad and dynamic Professional Learning Network is that, just when you feel like it’s all a bit too hard, something comes along and stokes the fires again.

Tonight I was participating in the #aussieED Twitter EdChat about the benefits of blogging both for students and for teachers. Some great individuals (@MRsalakas, @ZeinaChalich, just to name a few!) have shared their thoughts on what makes a good blog and how educators can use blogging to amplify the voices of ourselves and our students.

What I also found inspiring was the simple suggestions of everyday teachers from around the world on how we can better leverage blogging as a learning opportunity.

Tip:

#1, Get started (that’s my tip!)

#2. Write for you, not for others (@GeoMouldey)

#3 Keep it short (@diPrato)

#4 Focus on the ‘do’s’ rather than the ‘don’ts’ (@mythsysizer)

#5 Don’t get discouraged! (@joprestia)